net_dm: Add dissector for drop monitor netlink packets

The Linux kernel includes a module called drop monitor which -
unsurprisingly - monitors packet drops.

Once enabled, the module will periodically send netlink notifications to
user space over generic netlink. Historically, these notifications only
included the program counter where the drop occurred and the number of
packets that were dropped in this location in the last interval.

Patches in net-next (queued for Linux kernel 5.4) extend drop monitor
with another mode of operation where the dropped packets themselves are
sent to user space along with relevant metadata as netlink
notifications. This allows users to perform a more detailed analysis of
the dropped packets.

This patch adds a dissector for these netlink packets. The dissector is
expected to be invoked by the generic netlink dissector and during its
hand off routine it adds an entry in the 'genl.family' dissector table.

The various netlink attributes are dissected by calling
dissect_netlink_attributes(), in a similar fashion to the rtnetlink
dissector. The dropped packet itself is encoded in the netlink attribute
'NET_DM_ATTR_PAYLOAD' and dissected by invoking a dissector from the
'sll.ltype' dissector table based on the packet's protocol which is
encoded in the 'NET_DM_ATTR_PROTO' attribute.

Bug: 16018
Change-Id: I10bfa4b9c9d8f5e82769c250f929f74693142a23
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-on: https://code.wireshark.org/review/34351
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

0 files changed, 0 insertions, 0 deletions